WO20041114372A1 discloses a megasonic cleaner wherein the plate-like article is held between two plates (one plate holds ultrasonic transducers), the plate-like article and the transducer plate are rotated against each other.
Although this system brings very good cleaning results sometimes damages to the semiconductor devices and structures on the wafer occur.
Therefore it is an object of the invention to provide an apparatus and a method, which can be better monitored and if necessary even controlled in order to improve the treatment results.